Patent GB-190623075-A (GB)
Title: Improvements in Controllers for Electrically Propelled Vehicles.
Inventor: RAWORTH JOHN SMITH
Filed: 1906-10-18
Granted: 1907-02-28
Abstract: 23,075. Raworth, J. S., and Raworth, A. Oct. 18. Switches.-Relates to the series-parallel motor controller having a "floating ring," i.e. a set of segmental contacts having a certain amount of play over the drum, which is described in Specification No. 14,630, A.D. 1905. In the present case, the ring consists of two segmental parts in the same plane, and has two functions :-(1) to put resistances in and out of the armature circuit at different stages, according as the controller is being moved forward or backward; (2) to make some of the main barrel contacts applicable both for parallel and braking positions. The invention relates primarily to motors with shunt windings, but can also be employed in other motors for the second of the above - described purposes. The Figure shows two motors 1, 2 having shunt fieldwindings SF', SF<2>, series field windings F<1>, F', shunt field resistances SR', SR<2>, series field resistances RF<1>, RF<2>, and armature resistances R<1> ... R<1> The developed controller drum is shown to the right of the contact-fingers 65 &c. The braking-barrel X, which is on the same axis as the reversing barrel Y, is mechanically connected to the main barrel. In the 'off ' position, the braking-switch is necessarily set for 'running,' with the right-hand row of contacts on the fingers 2. Starting with the reversing-switch Y in the 'forward' position, the movement of the controller to the first position I puts the motors on the line in series with resistances R', R3,. R<4>, R<5>, and with full shunt excitation, the series field being out of use. The path of the current from the trolly contact 7 is. by the contacts 8, 9, the leads 10, 11, the resistances R' ... R<5>, the leads 12,13, the contacts 14, 15, 17, 18, 19, a lead 20, the contacts 21, 22, 23 of a cut-out switch W, the leads 24, 25, 26, 27, the motor armature the leads 28, 29, 30, 31, the contacts 32, 33, 34 of the cut-out switch W, the lead 35, the contacts 36, 37, 38, the contacts 40, 41, 42, 43, the lead 44,'the contacts 45, 46, 47, the lead 48, the contacts 49,- 50, 51, of a cut-out switch V, the leads 52, 53, the motor armature 2, the leads 54, 55, 56, the contacts 57, 58, 59 of the cut-out switch V, the lead 60, the contacts 61, 62, 63, the lead 64, the contacts 65, 66, 67, 68, the lead 69, the contacts 70, 71, 72, the lead 73, and finally to the earthed terminal E on a terminal-board Z, which is included in the controller case. The shunt path through the fields is by the contacts 7, 74, 75, the leads 76, 77, 78, the fields SF<1>, SF<2>, the leads 79, 80, 81, the blow-out coil 82, the lead 83, the contacts 84, 71 to the earthed terminal E. As the controller passes through the positions II and III, the resistances R<2>, R<3> are successively cut out of the circuit. At the position IIII, the forward part 93 of the floating ring comes into action and cuts out the remaining resistances R<4>, R<5>. As the controller leaves its position IIII, the contacts 74, 75 part, and insert the resistance SR<2> in the field circuit. At the next position V, the additional resistance SR' is put in the field circuit. There is no change of armature or field circuits at the subsequent positions VI to IX, the contact 93 keeping the armature resistance short-circuited. In passing between its positions IX and X, the controller puts the motors in parallel as compound machines. The armature circuit is broken and remade with the resistances R<3>, R<4>, R<5> in series, and all the shunt field resistance is cut-out. The series field-winding F<1> and the accompanying resistance RF<1> are put in series with the motorarmature 1, and the winding F<2> and resistance RF<2> in series with the armature 2. Each branch of the armature circuit lies through a separate cut-out switch of the pair V, W. At the positions XI and XII, the resistances R<3>, R<4> are successively cut out of the armature circuit. At the position XIII, the rear part 97<a> of the floating ring cuts out the resistance R<5>. The resistance SR<2> is also inserted in the shunt field circuit in moving from the position XIII, and the resistance SR<1> in moving, from the position XIV to the last position XV. When the': controller is moved backwards, the floating ring remains stationary until the position XIII, is passed, and is afterwards picked up and moved with the main barrel, occupying the positions shown in dotted lines. All the armature resistance is kept short-circuited until the change from parallel to series connexions. The circuit is broken as the controller leaves its position X, and remade in the position IX with the full resistance R<1> to R<5> in series. The changes that take place in the field windings are'the reverse of those' described in the forward movement. At the positions VIII and VII, the resistances R<1>, R<2>, R<3> are successively cut out. At the position VI, the floating ring cuts out the resistances R<4>, R<5>, which remain cut-out up to the position 1. The controller is capable of further movement in the same direction, which action sets the brake switch X to the other position. In the interval between leaving the position I and reaching the position XV, the controller closes the shunt field windings on themselves by means of the contacts 181, 182. At the position XV, the shunt field is connected again between the trolly and the earth terminal ; the armatures and seriesfields are in parallel for braking, with the resistances R<2> to R<5> in circuit, owing to the changed position of the floating ring. A balancing connexion across the armatures is made by the contacts 126<b>, 126<c> of the brake switch. The controller is moved on to its position XIV to form the second braking position, where the resistances R', R<3> are cut out. The final braking position XIII cuts out the resistances R<4>, R<5>. The same arrangement of the floating ring for braking is applicable for motors without shunt windings.